Stay bolt



Oct. 5,1926. I 1,601,845

R. S. BOOTH v STAY BOLT Filed Feb. 13, 1924 1; L? 1 h w 7 y 5 f vATTORNEYS til tenses ..,ran stares rarest orFicE.

ROBERT SINCLAIR BOOTH, OF WASHINGTON, DISTRICT OF COLUMBIA.

- STAY BOLT.

Application filed February 13, 1924. Serial No. 695,469.

This invention relates to flexible telltale staybolts for boilers, and,more particularly, for locomotive boilers; ject the provision of certainexpedients for continuing the tell-tale hole to the atmospheresurrounding the exterior of the boiler for more readily detectingdefects in such staybolts.

Rigid staybolts having tell-tale holes extending their entire length,or, at least, 1

inches deep from the outer end, have been universally employed for manyyears in the construction of locomotive boilers. Such staybolts aresubjected to excessive strain resulting in their fracture due to theunequal movement of the inner and outer sheets of the boiler or fireboxcaused by unequal expansion and contraction with changes in temperature.For this reason rigid staybolts, in spite of their advantage of having atell-tale hole extending their entire length, have been replaced in anumber of locomo tive boilers and fireboxes by so-called flexiblestaybolts. These flexible staybolts originally had no tell-tale hole,but lately have been equipped with a tell-tale hole extending only toone end and communicating with the flre box. The flexibility of suchstaybolts de: creases their liability to fracture, and for this reasonthey have been employed in the construction of certain portions oflocomotive boilers and fireboxes in preference to rigid staybolts. Theart clearly recognizes the utility of staybolts having a tell-tale holeextending their entire length or communicating with the exterior of theboiler and the atmosphere, as an element of safety. The ederal lawgoverning maintenance of locomotive boilers and the Interstate CommerceCommission, which is charged with the enforcement of said law, alsorecognize this fundamental principle.

Flexible staybolts now commonly employed are rigidly secured to theinner sheet shell or firebox side of the boiler and are flexiblyconnected with the outer or exterior sheet or shell of the boiler. Theflexible connection is closed by a cap or other suitable closure forpreventing leakage of water or steam. It has been found impracticable toemploy a flexible connection associated with the inner sheet shell orfirebox side of and has for its ob the boiler due to excessivecorrosionor other deleterious effects caused by high temperatures. v

The present invention contemplates the provision of certain expedientsfor continumg the tell-tale hole in flexible staybolts to the atmosphereby extending the tell-tale hole to the exterior of-t'he boiler withoutinterfering in any substantial manner with the flexibility of thestaybolt. Thus a flexible tube appropriately secured in the staybolt mayextend through the cap or closure so as normally to preventcommunication between the boiler and the tell-tale hole and continue thelatter to the exterior of the boiler or to the atmosphere. The tube maybe constructed of any suitable flexible material such as copper, lead,steel, brass, or aluminum, etc. The closure should be positioned aconsiderable distance from the head of the staybolt to permitconsiderable flexure of the tube. The flexibility of the tube may beincreased in various ways, such, for example, as reducing incross-section a portion of the tube. Or the flexibility of the tube maybe increased by curving the tube in the form, of a loop or winding,making a complete or partial turn.

The tube may be welded in the staybolt or closure, or otherwise securedtherein in any suitable manner to make an appropriate tight connectiontherebetween. Thus, the tube may be tapered at its ends for embedding inthe staybolt and the closure. Gr, alternately, the tube may be threadedat its ends and screwed into the staybolt andclosure, and, if desired anut or nut and gasket may be secured to the end of the tube in contactwith the closure to make a tight connection therebetween. I

These and other features of the invention will be more clearlyunderstood by reference to the following description and accompanyingdrawings; in Wl1lOl1-- Fig. 1 is a sectional view of a flexible stayboltassembled in, a boiler;

Fig. 2 is a plan view of the same; and

Figs. 3, 4:, and 5 are partial sectional views of modified forms of thestaybolt construction of the invention.

A staybolt 6 having a tell-tale hole 7 is screwed, or otherwise rigidlysecured, at one 12, as shown in Fig. 3.

as that previously described, or

end to the firebox shell 8 of a boiler to make a tight joint. The otherend of the staybolt is flexibly mounted upon the outer side of theexterior shell 9 of the boiler. Preterably, this end of the staybolt isrounded to bear upon the inner spherical surface of acollar or sleeve 10which is appropriately secured to the outer surface of the shell 9. Theflexible connection between the staybolt 6 and the collar or sleeve 10is closed by a removable cap or closure 11 to prevent leakage of wateror steam.

A. flexible tube 12 of any suitable material, such as copper, or lead,is appropriately secured in the end' of the'staybolt 6 and extendsthrough the closure 11 to continue the tell tale hole 7 through theclosure. The tube 12 may be screwed into either or both the staybolt andthe closure to make a water or steam tight joint, or the end of the tube12 may extend through the closure 11 and engage a threaded nut 13 havinga small depending circular projection 14 adapted to contact with a gaket 15 on the closure 11. Alternately, the tube 12 may have its endstapered in the same or opposite directions and adapted to be embedded inthe end of the staybolt and in the closure as shown in Figures 4 and 5.

The flexibility of the tube 12 may beincreased by reducing incross-section a por tion of its length. In certain portions of theboiler where the relative movement of the boiler shells is excessive, Ipropose to employ a modified form of a flexible tube The flexible tube12 may be secured to the staybolt 6 and closure 11 in any suitablemanner to make a water tight and steam tight connection, and

extends in a curved or winding path so as to form a complete or partialturn 'therebetween. If desired, the head of the'staybolt 6 may beflattened to provide increased space between the staybolt and theclosure. construction of flexible tube permits free turning of thestaybolt in its flexible bearing without danger of causing fracture inthe flexible tubular extension because of the increased flexibility ofthe tube in all directions.

The provision of a flexible tube in accordance with the inventioncontinuing the telltale hole to the exterior of the boiler and to theatmosphere will not materially interfere with the flexibility ofmovement of the staybolt, and willallow the discharge of steam or waterto the atmosphere when the staybolt becomes fractured sufficiently atany point to extend to the tell-tale hole, thus giving an automaticalarm in case of weakness or danger.

It will be understood that the flexible tube may be secured to thestayboltv and cap or closure in any manner whatsoever, such by auto-This the same direction genous welding, or by expanding, belling, orbeading the tube to make a steam tight fit.

As now required by law, the cap or closure must be removed at statedintervals for inspection of the staybolt and to permit suit-- able testbeing made, such, for example, as hammering the end o1 the staybolt todetect weaknesses or defects; it is also common practice to determinewhether or not the tell-tale hole is open by inserting a plunger thereinfrom the fire-box to make an electrical contact With'the bottom of thehole. The provision of the tubular extension of the tell-tale hole'tothe exterior of the boiler and atmosphere in accordance with the presentinvention should render unnecessary the removal of the cap or closurefor inspection and should eliminate such'other frequent tests as are nowcommonly required, inasmuch as any impending danger due to a weakness ordefect immediately apparent by the discharge of water orsteam.

The invention is applicable to boilers of any type wherever it isnecessary or desirable to stay the sheets or shells of a boiler or thesheet shell of a boiler firebox. Throughout this specification and theappended claims I intend the term shell to refer to or include the shellor sheet of a boiler, or the sheet shell of a boiler firebox, or anyother element with which a staybolt is ordinarily associated.

1 claim 1. In a flexible tell-tale staybolt construction for boilers, atell-tale staybolt having a flexible connection with the shell of theboiler, a closure for the flexible connection so positioned relative tothe staybolt as to provide a relatively large space therebetween, and aflexible tube extending through and secured to the closure and fixed tothe head of the staybolt to thereby extend the tell-taleto the exteriorof said closure.

2. A staybolt having a flexible connection with the shell of'a boiler, aclosure for the flexible connection, a tell-tale hole in the staybolt, aflexible tube secured in the closure and'terminating in the head of thebolt and continuing the tell-tale hole through the closure said tubehaving tapered ends adapted to 'be embedded in the staybolt and in theclosure to make a tight connection therewith.

3. In a flexible tell-tale staybolt construction for boilers, atell-tale staybolt adapted for flexible connection with the shell of theboiler, a closure forthe flexible connection, said staybolt being soconstructed and so positioned relative to the closure as to providearelatively large vspace therebetween, and a flexible tubejhaving endstapered in and extending through.

and secured to the closure and fixed to the in the staybolt is rendeed'head of the staybolt to thereby extend the to continue the tell-talehole therethrough, tell-tale hole to the exterior of said closure. saidstay-bolt having a flattened head to pro- 4. A staybolt having aflexible connection vide increased space between the staybolt 10 withthe shell of a boiler, a closure for the and the closure. 5 flexibleconnection, a tell-tale hole in the In testimony whereof I aflix mysignature.

staybolt, a flexible tube secured in the closure and terminating in thehead of the bolt ROBERT SINCLAIR :BOOTH.

